Saw guides

ABSTRACT

A method and apparatus for guiding a saw blade wherein the saw guides comprise opposed bearing shoes located on opposite sides of the saw blade, at least one of the bearing shoes urged toward each other and against the saw blade by an external force such as a compressed spring. Compressed air, water, water-air mixture or other fluid is supplied to the interior recesses of each of the bearing shoes and acts to form a fluid bearing surface at the bearing shoe-saw blade interface. The external force exerted on the bearing shoes is transmitted to the saw blade through the fluid medium with substantially no contact of the saw blade with the bearing shoes.

United States Patent usi 3,674,065

Fairfield, Jr. et sill.` y[45] ,f July v4, 1972 [541 SAW GUIDES3,419,097 11/1969 McLauhiana|.... 8s/201.1514

3,557,848 1/1971 wright ....143/160R [72] Inventors' 1'0" R' Fmed 3"Lmgvew 602,943 4/1898 Hinkley 143/160 Raymond A. Van Vliet, Mossyrock,both of Wash.; Thomas A. McLauchlan, Vancouver, British Columbia, CanadaAssignee: Weyerhaeuser Company, Tacoma, Wash.

Filed: July 6, 1970 Appl. No.: 60,979

Related U.S. Application Data Continuation of Ser. No. 725,566, April12, 1968, abandoned, Continuation-impart of Ser. No. 695,740, Jan. 4,1968, abandoned.

U.S.CL ..143/160 R,83/20l.l5, 143/157 C, 143/158, 143/164, 308/3 A Int.Cl ..B27b 5/28 Field ofSearch 143/160 R, 160 H, 157 C, 157 F, 143/158,164; 83/201.15; 308/3 A References Cited UNITED STATES PATENTS 3/ 1960Baumeister 3416/74 Primary Examiner-Andrew R. Juhasz AssistantExaminer-J ames F. Coan Attorney-Leslie G. Noller, John M. Crawford anW. Vernon [57] ABSTRACT A method and apparatus for guiding a saw bladewherein the saw guides comprise opposed bearing shoes located onopposite sides of the saw blade, at least one of the bearing shoes urgedtoward each other and against the saw blade by an external force such asa compressed spring. Compressed air, water, water-air mixture or otherfluid is supplied to the interior recesses of each of the bearing shoesand acts to forma fluid bearing surface at the bearing shoe-saw bladeinterface. The external force exerted on the bearing shoes istransmitted to the saw blade through the fluid medium with substantiallyno contact of the saw blade with the bearing shoes.

Kenneth PATENTEDJUL 41972 3. 574, O65 SHEET 1 nr 3 INVENTOR ou/s R.F4/RF/EL5 JA. RAYMOND A. VAN vLE/T THOMAS A. MAL/02A W- AWORNEYSPTENTEDJUL 41972 SHEET 2 UF 3 mvemons LOU/5 R. FAIRFIELD JR RAY/10MB A.VAN VLE/T THOZAS A. MLLAUCHLAN M ArroRNEYs sAw GUIDES CROSS REFERENCE TORELATED APPLICATION This is a continuation of Ser. No. 725,566, filedApr. l2, 1968, now abandoned, and which was a continuation-impart ofSer. No. 695,740, filed Jan. 4, 1968, also now abandoned.

BACKGROUND OF THE INVENTION 85 percent, percent of l. Field oftheInvention This invention relates to an improved method and apparatus forguiding saw blades, the improvement in the guides resulting in improvedcutting accuracy, improved surface finish, reduction of kerf, andminimum guide maintenance.

2. Prior Art Relating to the Invention Band and circular type power sawsrequire a means of guiding the saw blade so that they will cut astraight path. A conventional method of guiding circular saws has beensimple, solid blocks, usually lignum vitae, placed on-opposite sides ofthe saw blade. Continuous contact of these guides with the saw bladecannot be maintained because of frictional heating; thus the blade canonly be guided for short periods of time. In addition, guides of thistype do not stabilize or damp vibration of the saw blade.

Air under pressure has been used to align and guide saw blades. Such aguide system is disclosed, for example, in U.S. Pat. No. 3,225,801. Theprecision dimensional and surface tolerances required for this type ofgas bearing makes it impractical for saw guide application. ln addition,'such a gas bearing requires a great deal of air orother'ffluid'delivered under relatively high pressure with the guidingvforce being'effective only over a relatively narrow area.

SUMMARY OF THE INVENTION This invention relates to an improved methodand apparatus for guiding saw, whether circular, band, or gang. Theguiding means comprises a pair of opposed guide shoes through which thesaw blade travels. An external force is exerted on one or both of theguide shoes by compressed springs or other equivalent means. A fluidmedium, such as compressed air, water or water-air mixture is introducedunder pressure to an interior recess of each of the guide shoes, thefluid escaping along the bearing shoe rim and acting to support theguide shoes on a thin fluid film out of contact with the saw blade. Thefluid film, however, transmits the guiding force exerted on the guideshoes to the saw blade.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a perspective view of acircular saw showing one method of placement of the improved guides ofthis invention.

FIG. 2 is a cross section of the improved guide of this inventionwherein the external force exerted on the bearing shoe is provided bycompressed springs.

FIG. 3 is a view of section 3-3 of the guide of FIG. 2 showing the faceofthe bearing shoe.

FIG. 4 is a cross section of an alternate guide using compressed springsas the external force means.

FIG. 5 is a cross section of the improved guide wherein the externalforce exerted on the bearing shoes is provided by a resilient material.

FIG. 6 is a cross section of the improved guide wherein the externalguide force exerted on the bearing shoes is pneumatic.

FIG. 7 is a cross section of the improved guide system of this inventionillustrating a means of introducing a liquid solvent or lubricatingfluid with a gaseous fluid to the interior recesses of the bearingshoes.

FIG. 8 is a cross section of the improved guide system wherein one ofthe bearing shoes is fixed.

FIG. 9 is a cross-section of an alternate bearing shoe providing entryof compressed air or other fluid to the peripheral portions of thebearing shoe.

FIG. 10 is a front elevation of the face of the bearing shoe of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION FIGS. 2 to 8 illustrate variousconfigurations of the saw guide system of this invention. The basiccomponents of the saw guides include a bearing frame, bearing shoes,means to exert a force on the bearing shoes to urge one or both of theminto contact with the saw blade, and a conduit for supplying fluid,either liquid or gaseous, to the interior recessesof the bearing shoes.In FIGS. 2 to 9, reference numeral ll refers to v the bearing frame ontowhich bearing shoes l2 are mounted. Fluid is supplied to the interiorrecesses of bearing shoes 12 by conduits 13. An external force isexerted on one or both of the bearing shoes 12 by compressed springs 15as shown in FIGS. 2 and 3, pneumatic or hydraulic'means as shown inFIGS. 6 and 8, or by a resilient,elastomeric material 17 as shown inFIGS. 5 and 7. The external force exerted on the bearing shoe or shoesurges them into contact with saw blade 4 passing between the two opposedbearing shoes 12. By balancing the loading force on bearing shoes l2with the static pressure in the plenum 12b of each of the bearing pads,a clearance 14 between saw blade 4 and bearing rim 12a can beestablished.

The shape of the bearing shoes does not appear to be of criticalsignificance. They may be rectangular with rounded ends as shown in FIG.3 or circular as shown in FIGS. 4 and 9. A recessed plenum area 12b isnecessary for proper bearing operation. Beating lift is largelydependent on the fluid pressure and the bearing area. Stability isgreatly improved by using a recessed plenum to obtain more uniformpressure distribution. Plenum depth is not critical; however, it shouldbe at least 0.001 inch and preferably ranges from one-sixteenth toone-eighth inch. The bearing shoe may be of any suitable material havinga low coefficient of friction, such as bronzefilledpolytetrafluorethylene, polytetrafluorethylene, brass, nylon, 0r wood.

As mentioned previously, the external force applied to the bearing showmay be by compressed springs, pneumatic means, hydraulic means, orresilient, elastomeric material, such as sponge rubber. Control of thesaw blade 4 is accomplished by locating the bearing shoes on oppositesides of the saw blade as shown in FIGS. l to 9. Referring specificallyto the individual drawings, FIG. 2 shows a guide system with theexternal force exerted on bearing shoes 12 located on opposite sides ofsaw blade 4 by springs 15. In FIG. 4 springs l5 exert a guiding forceagainst bearing shoes 12 through 0-ring 16. In FIGS. 5 and 7, theexternal force is provided by elastomeric material 17. In FIGS. 6 and 8the external force exerted against bearing shoes 12 is provided bycompressed air, water or other hydraulic fluid entering chamber 22through conduit I8.

FIG. 8 shows a bearing system wherein one of the bearing shoes is xed,with the other urged against the saw blade by fluid pressure. When usingthis system the total force behind the movable guide shoe must bereduced sufficiently to allow the bearing pad to lift from the sawblade. The use of a fixed bearing shoe is advantageous in providing asaw location reference.

Fluid pressure introduced to the interior plenum of the bearing shoesexerts a force against the ground plane of the saw blade causing thebearing shoes to lift out of contact with the saw blade leaving a gap orbearing shoe-saw blade interface 14. The balance between the externalforce exerted on the bearing shoe and the static uid pressure in theplenum of the bearing determines the clearance at the saw blade-bearingrim interface 14. Referring to FIG. 6, utilizing a pneumatic orhydraulic external force, fluid pressure is introduced into plenumchamber 12b of bearing block l2 through conduit 13. Bearing shoe l2 ofFIG. 6 has a channel cut around its periphery and inlets channeled fromthe periphery to the interior to allow passage of the fluid to theinterior of the plenum chamber 12b of the bearing surface. Seals 20 arelocated as shown to prevent loss of pressure.

The most common fluid which can be used is, of course, compressed air;however, other gases can be used equally as well, such as carbondioxide, nitrogen, argon, helium, etc. Liquids, such as water and otherlubricating fluids, can also be used. The fluid pressure can beregulated to adjust the clearance at the interface 14. The guideconfigurations shown have a maximum efficiency of from 75 to 85 percent,that is, the load or external force that can be supported is 75 to 85percent of the product of the fluid pressure entering plenum 12b of thebearing shoe and the surface area of the shoe. A regulated line pressureof about 50 psi and a bearing surface area of 2 sq. in., for example,will support about 75 lbs. at a height of 0.001. Enough fluid pressureshould be used to permit a clearance at the saw blade-bearing shoeinterface 14 to permit passage of surface irregularities in the sawplate. The external force applied to the bearing pads is transmitted tothe saw blade through the fluid film at the bearing rim-saw bladeinterface 14. The fluid, however, does not contribute to the basic guidefunction.

In FIGS. 2 to 8 the fluid is introduced into the center of the bearingplenum chamber 12b. Fluid can be introduced around the periphery of theplenum chamber of the bearing shoe as shown by FIGS. 9 and 10 utilizingjets 13a. The peripheral jet bearing shoe must also include a plenumchamber 12b. If a flat surface bearing shoe were used having peripheraljets, it would require that each jet be supplied by an individuallyregulated source, thus making the use of flat surface bearing shoesimpractical for saw guide application.

Additional advantages can be obtained by using a gas-y liquid mixturefor injection into the plenum chamber 12b of bearing shoe 12. The liquidis preferably a lubricant and may be water, soluble oils, kerosene,ethylene glycol, etc. The lubricating fluid has the effect of fillingirregularities in the moving saw plate, thus eliminating a source ofvibration. Bearing stability is also increased because of the increasedstatic pressure in the presence of an incompressible fluid. Increasedpressures can also be used.

A liquid accelerated through the constriction 14 between bearing rim 12aand the surface of the saw blade penetrates the boundary air layer atthe saw blade surface, forming a thin liquid film on the saw bladesurface not affected by forces created by the moving saw blade. Neitheris this liquid film affected by passage of the saw blade through thecutting area during normal cutting conditions. The liquid film remainson the saw blade even while passing under a subsequent bearing or solidblock in contact with the saw blade forming a very eff fectivelubricant. Only very small quantities of liquid are needed to form thisliquid lm. Amounts as low as one-half gallon-hour have sufced on a 30foot saw plate; however, normal usage would be somewhat larger, forexample 2-3 gallons-hour.

ln this regard reference is made to FIG. l wherein a pair of opposedforce transmitting solid blocks 8 are used in conjunction with bearingshoes 6 and 7. These are preferably constructed from a low coefficientof friction material such as lignum vitae, bronze or a fluorocarbonpolymer. It should be noted that the solid guide blocks need not bepresent in opposed pairs. A single block acting against one side of theblade only is frequently very effective. In some saw constructions itmay be desirable to locate more than one solid pressure guide.Experience using water or other solvents applied through the bearingshoes has indicated no surface wear of the solid bearing block after 8hours of continuous operation, even with the bearing blocks under aconstant load of 50 to 100 psi. A coefficient of friction of about 0.015was measured between the bearing blocks of the type shown in thedrawings and the saw blade using a liquid applied along with compressedair to the plenum chambers of the bearing shoes. Attempts made to supplya similar liquid lm on the moving saw blade by spray mist, water jets,or flooding, failed to provide a lubricating surface such as achieved byinjection of the liquid into the plenum of the bearing shoe. Theseattempts failed as they were not able to penetrate and remove the movinglayer of air present on the surface of the rapidly moving saw blade.

One method of introducing liquid into a gaseous stream supplied to thebearing shoes is shown in FIG. 7 wherein'a liquid is introduced throughconduit 19 directly into the moving gaseous stream entering throughconduit 13. Valves 2l are used to regulate the amount of liquidintroduced. The liquid must be injected into the gaseous stream beforeentering the bearing pad.

The saw guides described are applicable to any saw type or thickness.Saw thicknesses ranging from 0.058 to 0.200 feet have been used.

Guides made according to this invention can be located on the saw platewhere most advantageous. Multiple guides can also be used. In FIG. 1 acircular saw blade 4 having a collar 3 and rotating about axle 2 passesbetween three bearing guides 6 and 7, and solid guides 8 held in placeby frame 1 as shown. Circular saws are guided most e'ectively with theguide located ahead of the cut When using thin kerf saws location of theguides below the cut is not as effective in preventing saw deviation orsniping.

The following examples illustrate the improvement attained in use of asaw guide system as described.

EXAMPLE I A guide system as shown in FIG. l was set up using a saw blade30 inches in diameter, 0.095 inches in thickness and having 60 teetheach 0.125 inches in width. The speed of the saw was approximately9,600l per minute. Two guides, supplied with compressed air or air-watermixture were located on the saw blade as shown by reference numerals 6and 7 of FIG. l. Lumber could be fed through the saw at a 4 inches depthat up to 700' per minute maximum with complete control. Line accuracywas 0.007 inches at the percent confidence level. The lumber describedhad excellent finish.

Without the guides in place, loss of control was experienced at 400' permin. with the best line accuracy at approximately per min. and i 0.050inches line accuracy at the 95 percent confidence level. The surfacefinish was affected by vibration of the saw blade.

EXAMPLE II Four inch lumber was sawed using a circular saw blade 0.072inches and 30 inches in diameter and having 60 teeth 0.092 inches wide.The speed of the saw was approximately 9,600' per min. Lumber was fedinto the saw at approximately 250' per min. Three guides, supplied withcompressed air or air-water mixture, were located as shown in FIG. l byreference numeral 6, 7, and 8. The reference numerals 6 and 7 denote thebearing guides while the reference numeral 8 denotes solid pressureguide blocks. Water injected through bearing guides 6 and 7 along withthe compressed air formed a lubricating film on the surface of the sawblade such that little or no wear of solid blocks 8 in pressure contactwith the saw surface occurred. Satisfactory performance was achieved forboth 2 inch and 4 inch lumber.

Without the guides the saw was completely unstable while running freeand could not be used for sawing operations.

What is claimed is:

1. Guide means for a saw blade comprising a. a pair of opposed bearingshoes having substantially coextensive opposing faces, the faces of thebearing shoes having a circumferential rim and a recessed interiorportion,

b. means to continuously apply an external guiding force to at least oneof the bearing shoes so as to continuously urge it toward the otherbearing shoe and against the side of a saw blade passing between, and

c. means directing fluid to the interior recesses of each of the bearingshoes under sufficient pressure to provide a fluid bearing surface atthe bearing shoe-saw blade interface for transmitting said guiding forcefrom said bearing shoe to said side of said saw while establishing aclearance between said shoe rim and said saw.

2. Guide means according to claim 1 wherein the external force isprovided by a compressed spring.

3. Guide means according to claim l wherein the external force isprovided by pneumatic means.

4. Guide means according to claim l wherein the external force isprovided by a resilient, elastomeric material.

S. Guide means according to claim 1 wherein one of the bearing shoes isfixed and immovable.

6. Guide means according to claim 1 wherein the bearing pad is composedof a material having a low coefficient of friction.

7. Guide means according to claim 1 including compressed air supplymeans in communication with said fluid directing means.

8. Guide means according to claim l including a liquid supply means incommunication with said fluid directing means.

9. ln a sawing machine having an endless saw blade which travels throughthe work zone of the machine the combination comprising a. a rigidsupport member,

b. a pair of opposed bearing shoes mounted on the supporting memberadjacent the point at which the saw blade enters the work performingzone, the bearing shoes having substantially coextensive opposing faces,the faces having a circumferential rim and a recessed interior portion,

c. means to continuously apply an external guiding force from saidsupport member to at least one of the bearing shoes to continuously urgeit toward the other and against the saw blade, and

. means directing a fluid to the interior recesses of each of thebearing shoes under sufficient pressure to provide a fluid bearingsurface at the bearing shoe-saw blade interface for transmitting saidguiding force from said bearing shoes to said saw blade whileestablishing a clearance between said rim and said saw blade.

l0. ln a sawing machine having an endless saw blade which travelsthrough the work zone of the machine the combination comprising a. arigid support member, l

b. a pair of opposed bearing shoes mounted on the supporting memberadjacent the point at which the saw blade enters the work performingzone, the bearing shoes having substantially coextensive opposing faces,the faces having a circumferential rim and a recessed interior portion.

c. means to continuously apply an external guiding force from saidsupport member to at least one of the bearing shoes to continuously urgeit toward the other and against the saw blade,

. means directing a fluid to the interior recesses of each of thebearing shoes under sufficient pressure to provide a fluid bearingsurface at the bearing shoe-saw blade interface for transmitting saidguiding force from said bearing shoes to said saw blade whileestablishing a clearance between said rim and said saw blade, and

e. a second rigid support member and at least one force transmittingbearing block mounted on the supporting member adjacent to the sawblade, the` bearing block mounted so as to contact the saw blade. 1 1.The sawing machine of claim 9 wherein the fluid is gaseous.

12. The sawing machine of claim 9 wherein the fluid is liquid.

13. The sawing machine of claim 9 wherein the fluid is a gas-liquidmixture.

14. A method of guiding a saw blade through a work performing zonecomprising a. providing a resilient guiding force against opposite sidesof a saw blade by exertion of continuous external pressure on bearingshoes whose faces are in contact with the saw blade, b. introducing afluid under pressure into a cavity in each of the opposed bearing shoesin contact with the saw blade, the fluid escaping from the guide shoerecesses along the bearing -shoe-saw blade interfaces, and c. regulatingthe fluid pressure at the bearing shoe-saw blade interfaces tosubstantially support the bearing shoes on a thin fluid film providingboth a fluid bearing surface and a medium to transmit the guiding forceexerted on the bearing shoes to the saw blade.

15. The method according to claim 14 wherein the fluid is a gas.

16. The method according to claim 14 wherein the fluid is a liquid.

17. The method according to claim 14 wherein the fluid is a gas-liquidmixture introduced into the bearing pad recesses, the liquid acting tolubricate and cool the saw blade.

18. The method according to claim 17 wherein the liquid is water.

19. The method according to claim 17 wherein the liquid is a solvent forremoving pitch and other residues from the surfaces ofthe saw blade.

20. The method of guiding a saw blade through a work perfonning zonecomprising a. providing a resilient guiding force against opposite sidesof a saw blade by exertion of continuous external pressure on bearingshoes whose faces are in contact with the saw blade,

b. introducing a fluid under pressure into a cavity in each of theopposed bearing shoes in contact with the saw blade, the fluid escapingfrom the guide shoe recesses along the bearing shoe-saw bladeinterfaces, said fluid is a gasliquid mixture introduced into thebearing pad recesses, the liquid acting to lubricate and cool the sawblade,

(c) regulating the fluid pressure at the bearing shoe-saw bladeinterfaces to substantially support the bearing shoes on a thin fluidfilm providing both a fluid bearing surface and a medium to transmit theguiding forces exerted on the bearing shoes to the saw blade, and

d. providing an additional guiding force against the saw blade by meansof at least one force transmitting bearing block in pressure contactwith the saw blade.

P04050 UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No.3 674 O65 Dated July 4 1972 It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

V" i "l In column l, line8, "85 percent, percent" should be deleted.

in column l, line 9, "of" should be deleted;

in column l, line 38, "saw," should read saws,;

in column 2, line 39, "show" should read -shoe; in column 3, line l3,i0.001." should read -0.00l inch.; in column 3, line 50,' "gallon-hour."should read --gallon/hour;

and "foot" should read --inch--; A

in column 3, line 52, "lons-hour" should read --lons/hour;

in Column 4, line 9, "feet" should read "inches".

Signed and sealed this 9th day of January 1973.

(SEAL) Attest:

EDWARD M. FLETCHER,JR.

Attestng Off]- CCT ROBERT yGOTTSCHALK Commissioner of Patents

1. Guide means for a saw blade comprising a. a pair of opposed bearingshoes having substantially coextensive opposing faces, the faces of thebearing shoes having a circumferential rim and a recessed interiorportion, b. means to continuously apply an external guiding force to atleast one of the bearing shoes so as to continuously urge it toward theother bearing shoe and against the side of a saw blade passing between,and c. means directing fluid to the interior recesses of each of thebearing shoes under sufficient pressure to provide a fluid bearingsurface at the bearing shoe-saw blade interface for transmitting saidguiding force from said bearing shoe to said side of said saw whileestablishing a clearance between said shoe rim and said saw.
 2. Guidemeans according to claim 1 wherein the external force is provided by acompressed spring.
 3. Guide means according to claim 1 wherein theexternal force is provided by pneumatic means.
 4. Guide means accordingto claim 1 wherein the external force is provided by a resilient,elastomeric material.
 5. Guide means according to claim 1 wherein one ofthe bearing shoes is fixed and immovable.
 6. Guide means according toclaim 1 wherein the bearing pad is composed of a material having a lowcoefficient of friction.
 7. Guide means according to claim 1 includingcompressed air supply means in communication with said fluid directingmeans.
 8. Guide means according to claim 1 including a liquid supplymeans in communication with said fluid directing means.
 9. In a sawingmachine having an endless saw blade which travels through the work zoneof the machine the combination comprising a. a rigid support member, b.a pair of opposed bearing shoes mounted on the supporting memberadjacent the point at which the saw blade enters the work performingzone, the bearing shoes having substantially coextensive opposing faces,the faces having a circumferential rim and a recessed interior portion,c. means to continuously apply an external guiding force from saidsupport member to at least one of the bearing shoes to continuously urgeit toward the other and against the saw blade, and d. means directing afluid to the interior recesses of each of the bearing shoes undersufficient pressure to provide a fluid bearing surface at the bearingshoe-saw blade interface for transmitting said guiding force from saidbearing shoes to said saw blade while establishing a clearance betweensaid rim and said saw blade.
 10. In a sawing machine having an endlesssaw blade which travels through the work zone of the machine thecombination comprising a. a rigid support member, b. a pair of opposedbearing shoes mounted on the supporting member adjacent the point atwhich the saw blade enters the work performing zone, the bearing shoeshaving substantially coextensive opposing faces, the faces having acircumferential rim and a recessed interior portion. c. means tOcontinuously apply an external guiding force from said support member toat least one of the bearing shoes to continuously urge it toward theother and against the saw blade, d. means directing a fluid to theinterior recesses of each of the bearing shoes under sufficient pressureto provide a fluid bearing surface at the bearing shoe-saw bladeinterface for transmitting said guiding force from said bearing shoes tosaid saw blade while establishing a clearance between said rim and saidsaw blade, and e. a second rigid support member and at least one forcetransmitting bearing block mounted on the supporting member adjacent tothe saw blade, the bearing block mounted so as to contact the saw blade.11. The sawing machine of claim 9 wherein the fluid is gaseous.
 12. Thesawing machine of claim 9 wherein the fluid is liquid.
 13. The sawingmachine of claim 9 wherein the fluid is a gas-liquid mixture.
 14. Amethod of guiding a saw blade through a work performing zone comprisinga. providing a resilient guiding force against opposite sides of a sawblade by exertion of continuous external pressure on bearing shoes whosefaces are in contact with the saw blade, b. introducing a fluid underpressure into a cavity in each of the opposed bearing shoes in contactwith the saw blade, the fluid escaping from the guide shoe recessesalong the bearing shoe-saw blade interfaces, and c. regulating the fluidpressure at the bearing shoe-saw blade interfaces to substantiallysupport the bearing shoes on a thin fluid film providing both a fluidbearing surface and a medium to transmit the guiding force exerted onthe bearing shoes to the saw blade.
 15. The method according to claim 14wherein the fluid is a gas.
 16. The method according to claim 14 whereinthe fluid is a liquid.
 17. The method according to claim 14 wherein thefluid is a gas-liquid mixture introduced into the bearing pad recesses,the liquid acting to lubricate and cool the saw blade.
 18. The methodaccording to claim 17 wherein the liquid is water.
 19. The methodaccording to claim 17 wherein the liquid is a solvent for removing pitchand other residues from the surfaces of the saw blade.
 20. The method ofguiding a saw blade through a work performing zone comprising a.providing a resilient guiding force against opposite sides of a sawblade by exertion of continuous external pressure on bearing shoes whosefaces are in contact with the saw blade, b. introducing a fluid underpressure into a cavity in each of the opposed bearing shoes in contactwith the saw blade, the fluid escaping from the guide shoe recessesalong the bearing shoe-saw blade interfaces, said fluid is a gas-liquidmixture introduced into the bearing pad recesses, the liquid acting tolubricate and cool the saw blade, (c) regulating the fluid pressure atthe bearing shoe-saw blade interfaces to substantially support thebearing shoes on a thin fluid film providing both a fluid bearingsurface and a medium to transmit the guiding forces exerted on thebearing shoes to the saw blade, and d. providing an additional guidingforce against the saw blade by means of at least one force transmittingbearing block in pressure contact with the saw blade.